Expansible cutter tool



May-ii), 1938. G. D. JOHNSON v EXPANSIBLE CUTTER TOOL Filed Nov. 50,1936 lemflyzzxag,

BY V

rmuwiww ATTORNEY.

Patented May 10, 1938 UNITED STATES PATENT OFFICE EXPANSIBLE' CUTTERTOOL Glenn D. Johnson, Compton, Calif., assignor to MacOlatchieManufacturing Company of Callzorrzila, Compton, CaliL, a corporation ofCali- Application November 30', 1986, Serial No. 113,297

' 11 Claims. (01. 255-76) This invention relates to expansible cuttertools and is particularly applicable to well drilling tools forenlarging the bore of a well, the invention being illustrated anddescribed in connection with that type of tool wherein an expansiblecutter scrapes the wall of the well bore.

It is an object of the invention to expand a cutter by relativelongitudinal movement of a mandrel, and to provide animproved operatingconnection between the mandrel and the cutter so arranged and of suchsize as to insure adequate strength and at the same time provide forappreciable expansion and permit complete contraction of the cutterwithin the body of the tool 5without unduly increasing the diameter ofsaid body.

It is a further object of the invention to provide a plurality ofcircumferentiallyspaced cut.- ters with an operating connection betweenthe mandrel and each cutter, and with the cutters laterally offset fromradii of the mandrel whereby a side of each of the cutters may partiallyoverlie the periphery of the mandrel to permit the cutters and theiroperating connections being of adequate size while adapted for receptionwithin restricted space in the body.

It is a still further object of the invention to particularly adapt theimproved operating connection for embodiment in a tool wherein themandrel may be operated, and a washing medium may be circulated through.the tool in accordance with usual practice as hereinafter described.

Further objects of the invention will be readily understood from thefollowing description of the accompanying drawing, in which:

Fig. 1 is a side elevation of the tool, partly in axial section andshowing the cutters contracted.

Fig. 2 is a similar view showing the cutters ex panded. Figs. 3 and 4are transverse sections on the lines 3-3 and 4-4 of Figs. 1 and 2respectively.

The invention is illustrated in connection with an expansible cuttertool for scraping the wall of a well bore, and in the illustratedembodiment of the invention the tool has three cutters equidistantlycircumferentially spaced. The cutters are mounted on a body I which isadapted for incorporation in a usual drill string, preferably by meansof a sub 2 which is threaded to the upper end of the body I and whichhas a threaded connection 3 at its upper end, with the lower end of thebody I also having a usual threaded conuection (not shown). The cuttersare mounted in slots 4 which are formed in the body I andwhichcommunicate with an axial bore 5 of the body. These slots, which in theillustrated embodiment of the invention are three in number toaccommodate the three cutters, are respectively parallel to threeequi-distantly circumferentially spaced radii A-0; B 0 and 0-0 oi. thebody I, and are eq'ui-distantly laterally oil'set from said radii in thesame circumferential direction as shown at Figs. 3 and 4, whereby thearea'oi' communication between each slot and-the bore 5 extends bem yondboth sides of that radius of the body lying perpendicular to the radiusto which the slot is parallel. For example, the slot 4 which is parallelto the radius A-O, communicates with the bore 5 at both sides of theradius A'-0 which is 1 perpendicular to the radius A-O.

A mandrel 6 is slidable in the bore I and an operating connection isprovided between the mandrel and each of .the cutters for expanding thelatter, with each operating connection 011- m cupying the space wherethe slot 4 for the corresponding cutter communicates with the bore 5.

As an instance of this arrangement the cutters are shown as pivotedcutters 1, adapted for swing-- ing movement to expanded position, andmay be 26 pivoted on pins 8 which extend across the slots 4 and whichmay be removably held in place as shown at 9. The cutters being mountedin the laterally offset slots 4, are thus similarly laterally oflsetwith relation to radii A--- 3-0 and 30 CO, and when contracted arecontained within the slots 4 as shown at Fig. 1, and when expanded swingoutwardly and upwardly to the position shown at Fig. 2, with theircutting edges Ia adapted to scrape the wall of a well bore when 5 thetool is rotated.

Lugs II project irom the bearing ends 10 of the cutters and are receivedin the portions of the 7 slots 4 which communicate with the bore I, the

lugs being preferably cut away at one side as 40 shown at Ila so as toclear the mandrel t; and

due to the laterally oii'set arrangement of the cutters with relationtoradii of the body I, the bearing ends 1c oi' the cutters may be of suchradius R as to slightly overlie the periphery of 45 the mandrel 6 asshown at S (Fig. 2-), while still clearing the mandrel as shown at Figs.3 and 4, and the lugs it may be of such sizeas to appreciably overliethe periphery of the mandrel as shown at T (Fig. 2), while stillclearing the 50 mandrel as shown at Figs. 3 and 4. Consequently thecutters may have a relatively large bearing radius R and their lugs Ii;may be of relatively large size, insuring desired strength for thecutters,

while still adapting the cutters 56 The operating connections for thecutters include abutments i2 on the mandrel 6 adapted to engage the lugsII, there being one of said abutments for each of the cutters. Eachabutment projects radially of the mandrel and of the body i,perpendicular to the radius to which the corresponding cutter isparallel. For example,- the abutment i2 for the cutter which is parallelto but laterally offset from the radius A-O, projects radially as shownat A'--O. Each of the abutments i2 is thus received in the portion ofthe corresponding slot 4 which communicates with the bore 5, and engagesthe corresponding lug ii transversely thereof and parallel to thepivotal axis of the corresponding cutter, so that when the mandrel 6 isprojected downwardly from the position shown at Fig. l to that shown atFig. 2, the abutments i2 engage the lugs ii and swing the cutters toexpanded position, while elevation of the mandrel to the position shownat Fig. 1 permits the cutters to swing to contracted position'receivedcompletely within the body I.

The mandrel 6 may be shifted to expand the cutters by fluid pressure inthe bore of the tool, and for this purpose the sub 2 may have a bore l5awhich forms a cylinder ii for 'a piston H, with the bore of the sub openat its upper end for communication with the bore of the drill string inwhich the tool is incorporated. The piston I1 is fixed to the upper endof the mandrel for pressure responsive downward movement in the cylinderso as to downwardly shift the mandrel, and the arrangement is preferablysuch that pressure of a washing medium in, the bore of the drill stringay be utilized for operating the piston, with a art of the washingmedium then preferably discharging at the expanded cutters, and theremainder of the washing medium discharging through the lower end of thebore 5.

As an instance of this arrangement the mandrel 6 may be a hollowmandrel, opening at its upper end into the cylinder I5 through thepiston l1, and opening at its lower end into the bore 5;, and aplurality of ports it, one for each of the cutters 1, are preferablyprovided in the peripheral wall of the hollow mandrel for lateraldischarge therethrough into the slots 4 immediately'belowthe cutters.When the cutters l are contracted and the hollow mandrel 6 is elevatedas shown at Fig. l, a plug 20 which is supported by the sub 2 preferablyextends into the upper end of the bore of the hollow mandrel so as toappreciably restrict flow through said bore and thus maintainappreciable pressure against the piston H for depressing the mandrel andthereby swinging the cutters toward their-operative position; but by thetime the piston has depressed the mandrel so as to expand the cutters,the piston will have been shifted clear of the plug 20 as shown at Fig.2, so that the entire flow through the drill string is then directedthrough the. bore of the mandrelfor discharge of a part of said fiowthrough the ports l8 and'thence through the slots 4 just below theexpanded cutters, and discharge of the remainder of the flow into thelower portion of the bore 5 and thence through the bore of that portionof the drill string which depends from the body I, so as to maintainusualcirculation.

Downward movement of the mandrel 6 is preferably terminated by thepiston i'l engaging" a cooperating abutment surface 22 at the upper endof the body I, and withthe parts in this position the mandrel haspreferably not yet swung the cutters to fully expanded position. Howeverthe cutters are so nearly fully expanded as to engage the wall of thewell bore so that the weight of the drill string completes the swingingmovement of the cutters to their fully expanded position as determinedby abutment of their surfaces lb against the upper, ends of the slots 4.This final swinging movement of the cutters after downward movement ofthe mandrel has been arrested; spaces the lugs II from the abutments IIas shown at Fig; 2, and as a result of this lost motion connection thetool may be operated with its cutters expanded, with no wear between thelugs II and the abutments l2.

when the cutters are to be contracted the drill string is elevated, andas a result of binding engagement of the expanded cutters with the wallof the well bore the cutters are swung toward their contracted position.Further contraction of the cutters results if the drill string iswithdrawn through an upper portion of the well bore, such as a casingstring, which is of smaller diameter than that defined by the expandedcutters, and during said contraction of the cutters the mandrel 6 ispreferably retracted by a spring 30 so that its abutments l2 offer noobstruction to free swinging movement of the cutters. The spring ispreferably mounted in the bore 5 around the mandrel 6, between-thepiston l1 and a supporting collar 3| which seats on a shoulder in saidbore. As soon as the force tending to hold the cutters in expandedposition is relieved by elevating the'drill string, the spring 30 thusretracts the mandrel so that the cutters are free for contraction.

The invention thus provides for utilizing cutters of maximum size andstrength while permitting their complete contraction within the body ofthe tool, due to the arrangement whereby the cutters are laterallyoffset from radii of the tool ,so as to in part overlie the periphery ofthe mandrel and thus conserve space, with the arrangement as thusdescribed permitting a simple operating connection between the mandreland the cutters, and also permitting operation of the mandrel andcirculation of a washing medium in accordance with usual and mostefllcient practice.

I claim:

1. In an expansible cutter tool, a body, a mandrel movable relative tothe body, a cutter carried by the body with its inner portion overlyingthe periphery of the mandrel, and an operating connection between themandrel and said overlying portion of the cutter for transverselyshifting the cutting edge of the cutter by longitudinal 'movement of themandrel.

2. In an expansible cutter tool, a body, a mandrel movable relativetothe body, acutter carried by the body in laterally offset relation toa radius of the body, and an operating connection between the mandreland the cutter transversely shifting the cutting edge of the cutter bylongitudinal movement of the mandrel.

3. In an expansible cutter tool, a body, a inandrel movable relative tothe body, a cutter carried by the body in laterally offset relation to aradius of the body so that cutter overlies the periphery of the mandrel,and an operating connection between the mandrel and said overlyingportion of the cutter for transversely shifting the cutting edge of thecutter by longitudinal movement of the mandrel.

4. In an expansible cutter tool, a body, a manthe inner portion of the2,116,898 drel movable relative to the body, a cutter carried a by thebody, a lug at the inner portion of the cutter overlying the peripheryof the mandrel, and an abutment on the mandrel for engaging the lug totransversely shift the cutting edge of the cutter by longitudinalmovement of the mandrel.

5. In an expansible cutter tool, a body, a mandrel movable relative tothe body, a cutter pivoted in the body with the inner portion of itsbearing overlying the periphery of the mandrel, a lug at the innerportion of said bearing overlying the periphery of the mandrel, and anabutment on the mandrel -for engaging the lug to swing the cutter bymovement of the mandrel.

6. In an expansible cutter tool, a body having an axial bore and a slotin laterally offset relation to a radius of the body and communicatingat its inner end with the axial bore, a mandrel in the axial bore, acutter mounted in theslot with its inner portion overlying the peripheryof the mandrel, and an operating connection between the mandrel and saidoverlying portion of the cutter for transversely shifting the cuttingedge of the cutter by longitudinal movement of the mandrel.

7. In an expansible cutter tool, a body, a hollow mandrel movablerelative to the body, the hollow mandrel being adapted to receivedrilling fluid and having a lateral outlet for said drilling fluid, aplurality of cutters carried by the body with the inner portions or thecutters overlying the periphery of the mandrel in equi-distantlycircumferentially spaced relation, and an operating connection betweenthe mandrel and the inner portion of each of the cutters fortransversely shifting the cutting edges of the cutters by longitudinalmovement of the mandrel, said abutment being longitudinally above theoutlet.

8. In an expansible cutter tool, a body, a mandrel movable relative tothe body, a cutter carried by the body with its inner portion overlyingthe periphery of the mandrel, and an operating connection between themandrel and said overlying been stopped.

portion of the cutter for transversely shifting the cutting edge of thecutter by longitudinal movement of the mandrel, the mandrel being hollowand adapted for flow therethrough and discharge therefrom laterally pastthe cutter.

9. In an expansible cutter tool, a body, a mandrel movable relative tothe body, a cutter carried by the body with its inner portion overlyingthe periphery of the mandrel, and an operating connection between themandrel and said-overlying portion of the cutter for transverselyshifting the cutting edge of the cutter by movement of the mandrel, thecutting edge of the cutter in extended position being verticallydisposed and forming a cutting edge of appreciable length, the mandrelbeing hollow and adapted forfiow therethrough and having a port in itsperipheral wall for lateral discharge therethrough adjacent the cutter.-

10,. In an expansible cutter tool, a body, a mandrel movable relative tothe body, a cutter carried by the body with its inner portion overlyingthe periphery of the mandrel, an operating connection betweentthemandrel and said overlying portion of the cutter for transverselyshifting the cutting edge of the cutter by longitudinal movement of themandrel, and fluid pressure means for moving the mandrel.

11. In an expansible cuttertool, a body, a hollow mandrel movablerelative to the body, the hollow mandrel being adapted to receivedrilling fluid and having a lateral outlet for said drilling fluid, acutter carried by the body with its inner portion overlying theperiphery of the mandrel, an operating connection between the mandreland said overlying portion of the cutter for transversely shifting thecutting edge of the cutter by 'movement of the mandrel, and means forlimiting said movement of the mandrel, the operating connectionpermitting continued shitting of the cutter after said movement of themandrel has GLENN D. JOHNSON.

